Engine



July 20, 1965 R. c. HEIDNER 3,195,524

ENGINE Filed July so, 1962 INVENTOR. fin/44w d Am/vm wmmym United States Patent 3,195,524 ENGINE Richard C. Heidner, Libertyville, 111., assignor to Outboard Marine Qorporation, Wauiregan, 111., a corporation of Delaware Filed July 30, 1962, Ser. No. 213,241 14 Claims. (Cl. 123-73) The invention relates generally to two-stroke, spark ignition, internal combustion engines. More particularly, the invention relates to the problem of reducing the excessive fuel waste which commonly occurs during idling or closed throttle operation of such two-stroke engines.

Because of the air-fuel mixture supply and exhaust gas porting arrangement normally employed in two-stroke engines, the quantity of air-fuel mixture entering into the cylinder during idling or closed throttle operation is supplied, at least in part, for the purpose of scavenging the burned gases resulting from the previous firing and is materially in excess of the quantity required to maintain the engine running. With such excess air-fuel mixture, the firing of the spark plug is generally retarded or delayed to limit the power developed during the stroke.

The invention herein disclosed takes advantage of the fact that during idling or closed throttle operation, it is unnecessary to exhaust all of the burned gases or other contaminates from the cylinder, so long as there is provided, in the area of the spark plug, a Zone containing an air-fuel mixture which is within flammability limits. The invention provides an arrangement whereby, during idling or low speed operation, the normal or primary airfuel mixture supply passageway, as for instance, the transfer passage, is closed and a limited quantity of air-fuel mixture is supplied by an auxiliary or secondary flow passageway directly to the area of the spark plug.

The invention also provides for closing the auxiliary flow passageway during high speed engine operation and for coordinating the opening and closing of both the primary and secondary passageways.

Other objects and advantages of the invent-ion will become known by reference to the following description and the accompanying drawings of the invention, in which:

FIGURE 1 is a fragmentary, partially broken away, sectional view of an engine 11 embodying various of the features of the invention;

FIGURE 2 is an enlarged, fragmentary sectional view of an engine 111, showing a modified arrangement for closing a transfer passage;

FIGURE 3 is an enlarged, fragmentary sectional view of an engine 211 showing a modified arrangement for valving a transfer passage and an auxiliary passageway; and

FIGURE 4 is a sectional view taken generally along line 4- 1 of FIGURE 1.

The two-stroke engine 11, shown in FIGURE 1, includes a cylinder 13, a spark plug extending into the cylinder 13, a reciprocably movable piston 17 in the cylinder 13,

and a crankcase 19 extending from the cylinder 13. As

is usual in two-stroke engines, the crankcase 19 is closed except for a combustion air-fuel mixture supply port which leads to a carburetor, or the like, and which is controlled by suitable valve means, such as a reed valve 18 responsive to the cyclical pressure condition created in the crankcase by reason of the piston movement. The piston 17 is connected to a crankshaft 20 by a connecting rod 21 and the cylinder 13 is provided, in the usual fashion, with a Water jacket 23 for cooling purposes.

As is also conventional, the cylinder 13 includes an exhaust port 25 which is generally located in diametrically opposed relation to an intake port 27 constituting one end of a transfer or bypass passage 29 leading to the crankcase 19. The transfer passage 29 and port 27 constitute a primary passage or means for supplying a combustion air-fuel mixture to the cylinder. The piston skirt constitutes one means for opening and closing the intake port 27.

Increased fuel economy is obtained, when the engine is operating at low or idling speeds, by providing means for conducting to the cylinder 13 only such quantity of combustion air-fuel mixture which will support continued operation of the engine 11, which quantity of combustion air-fuel mixture is conducted or directed to the area immediately adjacent the spark plug 15. Thus, in accordance with the invention, the engine 11 includes an auxiliary passageway 31 connecting the crankcase 19 to the cylinder 13 preferably in the area adjacent to the spark plug 15. In addition, the engine 11 incorporates means for opening and closing the auxiliary passageway 31 in response to piston movement, and valve means for closing the transfer passageway 29 to prevent or substantially reduce flow therethrough when the engine is operating respectively at idling and low speed conditions, and to permit full opening of the transfer passage 29 when the engine is operating at high speeds.

Various arrangements can be employed for positively opening and closing the auxiliary passageway in response to piston movement. Preferably, said arrangement for positively opening and closing the auxiliary passageway affords flow and subsequently precludes flow of combustible mixture to said cylinder through said auxiliary passageway before the occurrence of substantial compression of the charge in the cylinder. For instance, a cam-shaft operated means functioning in co-ordination with piston movement could be employed. In the disclosed construction, the auxiliary passageway 31 is opened and closed directly in response to piston movement. More specifically, the piston 17 includes a skirt 35 having an aperture 37 therein and the auxiliary passageway 31 terminates in an opening 39 in the cylinder wall in position to register with the aperture 37 in the piston skirt 35 when the piston is at, or near, bottom dead center, thereby connecting the auxiliary passageway 31 to the crankcase 19 When the crankcase is under positive pressure. When the piston moves from bottom dead center, the opening 39 at the end of the auxiliary flow passageway 31 is closed by the piston skirt 35 and remains closed until the piston 17 again approaches bottom dead center.

As already noted, the discharge end of the auxiliary flow passageway 31 preferably communicates with the cylinder 13 in the area adjacent to the spark plug 15, as shown in FIGURE 1. If desired, the cylinder head can be specially formed to provide a sub-chamber located adjacent to the spark plug, such as shown at 41, for receiving the combustion air-fuel mixture. Use of a sub-cham 'ber, such as shown in FIGURE 1, serves to retain the charge supplied through the auxiliary flow passageway 31 in concentrated condition adjacent to the piston. However, the use of the particular configuration, shown in the drawings is not critical and the advantages of the invention can be substantially achieved even without a welldefined sub-chamber.

If desired, the auxiliary flow passageway 31 can be closed, when the engine is operating at high speeds, by Valve means 43 regulated by an engine-speed controlling member or shaft 44. There is shown in FIGURE 1 a valve member 45 which is located in the flow passageway 31 and which is mounted on a shaft 47 rotatably supported by the fiow passageway 31 and carrying, externally of the passageway 31, a bevel gear (not shown) meshed with a bevel gear (not shown) carried on the shaft 46. Also carried on the shaft 46 is a second bevel gear 48 which meshes with a bevel gear 5% on the engine speed controlling shaft 44. The shaft 47 can also be rocked to open and close the valve member 45 relative to therauxiliary flow passageway 31 by various other arrangements for coupling the shaft 47 to an engine-speed controlling member so as to. effect closing'of the valve memberwhen the, engine is operating at high speed and opening of the valve member when the engine is operatin g-at low or idling speeds;

Various primary means or arrangements can be employed for opening and closing the transfer passage 29 in accordance with the engine speed. In FIGURE 1 there is shown a flat valve member 52 which is mounted within the transfer passageway 29 for movement to and from a position closing the passageway 29 on a shaft 51 rota. tablysuppor-ted by the walls of the transfer passage. In

turn, the shaft 51 carries a bevel gear .(not shown), in

mesh with another bevel gear (not shown). mounted on a shaft 54. Also carried .by the shaft 54 is a bevel gear 56in mesh with another bevel gear -58 on the engine speed controlling shaft 44. Other suitable arrangements can be employed to close the valve member 52 .when

operatingt-he engine at low or idling speeds and to open the valve memberSZ when operating the engine at high speed, thereby co-ordinating activity of the valve members 45 and 52.

In FIGURE 2 there for movement of its head 153relative to the intake port 127 so as to effect opening and closing thereof. The wall of the transferpassage 129 is also provided. with a recess or seat'1 55 for receiving the head 153 in order to obtain a substantially unobstructed passage when theengine 111,

is operating at high speeds. V

Movement of the valve member head .153 relative to the intake port 127.. is provided by forming the valve member 149 with an extension 157 projecting out of the is shown another form of valve 7 means 133 for opening and closing communication transfer passage 129 and by including on the extension 157 a worm 159 which is enmeshed with a worm gear 161 carried on a rotatable shaft 163 constituting an engine-speed controlling member toeffect closing of :the valve member relative to the intake port 127 whenoperat ing the engine at idling or low speed and opening of the valve member when operating the engine at high speed.

In the arrangement shown in FIGURE 3, the, auxiliary flow passageway 231 is an extension of the transfer passage 229 and terminates in an orifice or port 263in the Wall of the cylinder 213 adjacent to the intake port 227. In this-arrangement, a deflecting surface 265 on the top face of the piston 217 is employed to carry or direct the charge to the area of the spark plug. If desired, 'the flow passageway can terminate in the cylinder wall at i a point closer to the spark plug to reduce the chance of dilution incident to travel of the charge within the cylinder. However, in any event/the. port 263 at the dischargeend of the flow passageway 231 should beclosed by the piston 217'before ignition of the charge. I

In'the arrangement shown in FIGURE 3, the, transfer passage 229' and the flow passageway 231 are controlled by a single valve member 249. More specifically, the valve member 249 is carried on a shaft 251 rotatably supported by the walls of the transfer passage 229 and is movable, incident to rocking of the shaft 251, between a first position closing the intake port 227 at the end of the transfer passage 229, while leaving the flow passageway 231 open, and a second position closing the flow passageway 231 while leaving the intake port 227 open;

Any suitable arrangement can be employed for coupling 7 low idling speeds and for moving the valve member to its the engine is operating at high second position when p e s. w

Various of the features of the invention are set forth in the appended claims.

What is claimed is:

1. In an internal combustion engine including a cylinder, primary means including apassage for supplying a combustion air-fuel mixture to said cylinder, valve means for opening and closing said primary mixture supply means connected to. anengine-speed controlling member, a piston reciprocably' operablei-n saidcylinder, means for opening and closing-said primary mixture supply means in co-ordination with movement ofsaid piston and independently of said valve means, and means for ,conducting combustion air-fuel mixture to said cylinderindependently of said primary supply means including an auxiliary flow passageway communicating with said cylinder for supplying a combustion air-fuel mixture, and means on said piston for opening and closingrsaid auxiliary flow passage in co-ordination with movement 'of said piston. p f I a 2, An engine in accordance with claim 1 including second valve means for opening and closing saidaux iliary flow passageway independently of the movement of said piston. P p Y 3. An engine in accordance with claim lj'wherein sfaidvalve means comprises a rotatably mounted: valve member located in saidtransfer passage for opening and closing movement relative to a position closing said passage.

, 4. Aneng-ine in accordance with claim 1 wherein said transfer passage terminates with an intake port in the wall of said jcylinder and said valve means comprises a ,valve member supported for linear movement radially of said cylinder relative to said intake port to open and closeisaid port.

5 An engine in accordance with claim 4 whereinsaid valve member includes a head,iand

said transfer passagev includes a, seat for receiving said head when said valvemember is positioned in radially spaced relation from said intake port.

6. two stroke engine including anengine speed controlling member, a cylinder, a spark plug extending into saidcylinder, a crankcase connected to said cylinder and being rotherwise closed except for a combustion air-fuel mixture intake, a transfer passage connecting said crankcase to said'cylinder for supplying a combustion air-fuel mixture from said crankcase to said cylinder, a piston reciprocably operable in said cylinder to close said transferpassage in response to movement of said piston from bottom dead center, valve means in said transfer passage and connected to said engine-speed controlling member for opening and closing said transfer passage independently of said piston, and means for conducting combus tion air-fuel mixture from said crankcase to said cylinder independently of the open or closed'condition of said transfer passage including an auxiliary passageway communicating with said crankcase and with said cylinder in the area adjacent to said spark plug, and means for open- ,ing and closing said passageway inco-ordination with movementof said piston.

7. Animproved wherein said valve means comprises a rotatably mounted valve member located in saidtransfer passage for opening and closing movement relative to. a position closing 7 said passage; 7 V v 8. An improved engine in accordance with claim 6 wherein in p i said transfer passage terminates with an intake port in the wall of said cylinder and said valve means comprises a valve member supported for linear movement radially of said cylinder relative to said intake port to openand close said-port, s v

' '9. In atwo stroke engine includinga cylinder, a spark plug extending into said cylinder, a*crankcase connected to' said cylinderandtbeing ,otherwiseclosed except for engine in accordance withclaim 6 a combustion air-fuel mixture intake, and a transfer pasv sage connecting said crankcase to said cylinder for supplying a combustion air-fuel mixture from said crankcase to said cylinder, a piston reciprocably operable in said cylinder to close said transfer passage in response to movement of said piston from bottom dead center,

an auxiliary passageway communicating with said crankcase and with said cylinder for conducting combustion air-fuel mixture from said crankcase to said cylinder,

means for positively opening and closing said passageway incident to movement of said piston, and

valve means in said transfer passage and connected to an engine speed controlling member for movement between a first position in which said transfer passage is open and a second position in which said transfer passage is closed.

10. An engine in accordance with claim 9 wherein said valve means is also operable to close said auxiliary passageway when said valve means is in said first position and to open said auxiliary passageway when said valve means is in said second position.

11. In a two stroke engine including a cylinder, a spark plug extending into said cylinder, a crankcase connected to said cylinder and being otherwise closed except for a combustion air-fuel mixture intake, and a transfer passage connecting said crankcase to said cylinder for supplying a combustion air-fuel mixture from said crankcase to said cylinder, a piston reciprocably operable in said cylinder to close said transfer passage in response to movement of said piston from bottom dead center, said piston including a skirt having an opening therein, said opening communicating with said crankcase,

means defining an aperture in said cylinder positioned to register with said opening in said piston skirt when said piston is adjacent a bottom dead center position and to be closed by said skirt in response to piston movement from said bottom dead center position, and

an auxiliary combustion air-fuel mixture passageway communicating with said aperture defining means in said cylinder and with a port opening into said cylinder at a point spaced from said aperture defining means, whereby when said piston is adjacent said bottom dead center position said passageway affords communication between said crankcase and said cylinder.

12. In a two stroke engine including a cylinder, a spark plug extending into said cylinder, a crankcase connected to said cylinder and being otherwise closed except for a combustion air-fuel mixture intake, and a transfer passage connecting said crankcase to said cylinder for supplying a combustion air-fuel mixture from said crankcase to said cylinder, a piston reciprocably operable in said cylinder to close said transfer passage in response to move- 6 ment of said piston from bottom dead center, said piston including a skirt having an opening therein said opening communicating with said crankcase, means defining an aperture in said cylinder positioned to register with said opening in said piston skirt when said piston is in one position and to be closed by said skirt in response to piston movement from said one position, an auxiliary combustion air-fuel mixture passageway communicating with said cylinder and with said means defining an aperture in said cylinder, whereby when said piston is in said one position said passageway affords communication between said crankcase and said cylinder, and valve means in said transfer passage and connected to an engine speed controlling member for opening and closing said transfer passage. 13. An engine in accordance with claim 12 wherein said one piston position occurs when said piston is adjacent bottom dead center, whereby the pressure condition in said crankcase is effective to flow a quantity of the combustion air-fuel mixture through said passageway to said cylinder. 14. An internal combustion engine including a cylinder, a piston reciprocable in said cylinder to compress successive charges of combustible mixture supplied to said cylinder in response to piston movement from a bottom dead center position, a spark plug in said cylinder, means for supplying combustible mixture to said cylinder including a primary passage communicating with said cylinder at a first point, an auxiliary passage communicating with said cylinder at a second point less remote from said spark plug than said first point, means affording flow and subsequently precluding flow of combustible mixture to said cylinder through said auxiliary passageway before the occurrence of substantial compression of the charge in said cylinder, means for varying relative flow through said passages, and means for regulating said flow varying means to provide for relatively decreasing flow through said primary passage as compared to said auxiliary pas sage in response to decreasing engine speed.

References Cited by the Examiner UNITED STATES PATENTS 842,392 1/07 Eckard 12373 1,101,374 6/14 Woolery 123-73 2,481,901 9/49 Bracke 123-73 FOREIGN PATENTS 681,793 10/39 Germany.

FRED E. ENGELTHALER, Primary Examiner. 

1. IN AN INTERNAL COMBUSTION ENGINE INCLUDING A CYLINDER, PRIMARY MEANS INCLUDING A PASSAGE FOR SUPPLYING A COMBUSTION AIR-FUEL MIXTURE TO SAID CYLINDER, VALVE MEANS FOR OPENING AND CLOSING SAID PRIMARY MIXTURE SUPPLY MEANS CONNECTED TO AN ENGINE-SPEED CONTROLLING MEMBER, A PISTON RECIPROCABLY OPERABLE IN SAID CYLINDER, MEANS FOR OPENING AND CLOSING SAID PRIMARY MIXTURE SUPPLY MEANS IN CO-ORDINATION WITH MOVEMENT OF SAID PISTON AND INDEPENDENTLY OF SAID VALVE MEANS, AND MEANS FOR CONDUCTING COMBUSTION AIR-FUEL MIXTURE TO SAID CYLINDER INDEPENDENTLY OF SAID PRIMARY SUPPLY MEANS INCLUDING AN AUXILIARY FLOW PASSAGEWAY COMMUNICATING WITH SAID CYLINDER FOR SUPPLYING A COMBUSTION AIR-FUEL MIXTURE, AND MEANS ON SAID PISTON FOR OPENING AND CLOSING SAID AUXILIARY FLOW PASSAGES IN CO-ORDINATION WITH MOVEMENT OF SAID PISTON. 